20561617326 has 64 divisors (see below), whose sum is σ = 43427155968. Its totient is φ = 6477512448.

The previous prime is 20561617289. The next prime is 20561617333. The reversal of 20561617326 is 62371616502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4213600 + ... + 4218476.

It is an arithmetic number, because the mean of its divisors is an integer number (678549312).

Almost surely, 2^20561617326 is an apocalyptic number.

20561617326 is an abundant number, since it is smaller than the sum of its proper divisors (22865538642).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20561617326 is a wasteful number, since it uses less digits than its factorization.

20561617326 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5265.

The product of its (nonzero) digits is 90720, while the sum is 39.

The spelling of 20561617326 in words is "twenty billion, five hundred sixty-one million, six hundred seventeen thousand, three hundred twenty-six".